Production of motor fuels by solvent extraction



Patented June 23, 1942 PRODUCTION OF MOTOR FUELS BY SOLVENT EXTRACTIONArthur B. I-Iersberger, Lansdowne, Pa., assignor to The AtlanticRefining Company, Philadelphia, Pa., a corporation of Pennsylvania NoDrawing. Application May 16, 1939, Serial No. 273,890

6 Claims.

The present invention relates to the production of motor fuels ofimproved combustion characteristics, and relates more particularly tothe production of gasoline of improved anti-knock value and to theproduction of compression ignition fuel, such as Diesel fuel, ofimproved cetane value. In general, the fuels to be treated .inaccordance with this invention are distillate fuels such as crackedgasoline, kerosene, and gas oil, which fuels comprise mixtures ofhydrocarbons of various types, including paraffins, ole-fines,aromatics, and naphthenes.

Fuels designed for use in spark-ignition engines, particularly engineshaving a high compression ratio, are characterized in having arelatively high anti-knock or octane value, and gasolines containing arelatively large proportion of aromatics, olefines, naphthenes orbranched-chain paraffins exhibit this desirable property. On the otherhand, fuels designed for use in compression engines, such as Dieselengines, are characterized in having a relatively high cetane value, andkerosenes or gas oils containing relatively large proportions ofparaffin hydrocarbons, particularly straight-chain paraflinhydrocarbons, -or naphthenes containing long hydrocarbon chains, exhibitthis property. The cetane value of compression ignition fuels may betaken as indicative of the combustion characteristics of the fuel, i.e., the higher the cetane value, the lower the ignition temperature ofthe fuel :and the shorter the delay period between the injection andignition of the fuel. Paraffin hydrocarbons, in general, possess lowerspontaneous ignition temperatures than the aromatic hydrocarbons, and itis therefore desirable to retain the paraflin hydrocarbons incompression ignition fuels, whereas the aromatic hydrocarbons arepreferably retained in spark ignition fuels such as gasoline.

It is therefore-an object of thisinvention to produce gasoline ofimproved anti-knock value from gasoline distillates comprisingcomponents having relatively higher and lower anti-knock values byseparating from the distillate those components having relatively higheranti-knock value, and employing such components as motor fuel.

It isa further object of this invention to produce "compression ignitionfuels, such as Diea nition temperatures, and employing such componentsas compression ignition fuel.

In accordance with the present invention, the separation of hydrocarbonoil distillate into fractions having different physical and chemicalproperties, and therefore different combustion characteristics, isaccomplished by contacting the distillate with a solvent comprisingmorpholine, whereby the aromatic, olefinic, and naphthenic hydrocarboncomponents are dissolved in the solvent and may be separated from theundissolved, more parafiinic hydrocarbon components.

In the case of a gasoline distillate containing relatively higher andlower anti-knock components, i. e., aromatic components, and paraffiniccomponents, respectively, the components removed'from the distillate byextraction will constitute the fraction having the higher anti-knockvalue, and the components remaining undissolved will constitute thefraction having a lower antiknock value.

However, in the case of a fuel oil distillate, such as gas oilcontaining relatively higher and lower spontaneous ignition temperaturecomponents, i. e., aromatic components, and parafiinic components,respectively, the components removed from the distillate by extractionwill constitute the fraction having the higher spontaneous ignitiontemperature, and the components remaining undissolved will constitutethe fraction having aflower spontaneous ignition temperature, whichfraction is more desirable for use as a compression ignition fuel.

In carrying out the method of the present invention, the oil distillateis commingled or contacted with a solvent comprising morpholine, at atemperature below the miscibility temperature of the distillate and thesolvent, whereby two liquid phases are formed, one phase comprising themajor portion of the solvent containing the aromatic and/or naphtheniccomponents dissolved therein, and the second phase comprising theundissolved,more parafiinic components containing a minor portion of thesolvent. The two phases are separated from one another, for example, bydecantation or centrifuging, and the solvent removed from each, forexample, by water washing, or by distillation in the event that theboiling point of the solvent is sufficiently different from the boilingrange of the oil components. The extraction process may be carried on ina batch system, a multiplebatch countercurrent system, or a continuouscountercurrent system, the latter being preferred.

While morpholine, per se, may be employed as the selective solvent forthe aromatic and/or naphthenic oil components, the extraction mustusually be performed at relatively low temperatures, i. e., of the orderof F. or lower, since the morpholine is completely miscible with the oildistillate except at very low temperatures. In order to overcome thisdifficulty, it is preferable to employ morpholine admixed with an agentcapable of increasing the miscibility temperature of the morpholine withthe oil. Among the agents which may be suitably employed to this end arethe water-soluble, lower aliphatic alcohols having less than 4 carbonatoms per molecule, i. e., methyl alcohol, ethyl alcohol, propylalcohol, isopropyl alcohol, ethylene glycol, and glycerol. The volumeratio of alcohol to morpholine may vary within the range of from about1:1 to 1:10, depending upon the temperature at which the extractionprocess is to be carried out and the character of the oil frac tions itis desired to produce. The volume ratio of solvent to oil may varywithin the range of from about 0.5:1 to 5:1, and is preferably of theorder of 1:1. In lieu of, or in addition to morpholine, I may employmorpholine derivatives, such as methyl morpholine, ethyl morpholine, orthe halogenated morpholines, e. g., chloro-morpholine, in the selectiveextraction of hydrocarbon oils.

My invention may be illustrated by the following example, which,however, is not to be construed as limiting the scope thereof:

A gasoline distillate produced by cracking hydrocarbon oil at elevatedtemperature and pressure, and having a distillation range of from 100 F.to 390 F., and A. P. I. gravity of 58.4", an aniline number of 42.8, andan octane value of 66, was admixed with a solvent comprising 83%morpholine and 17% methyl alcohol, in the volume ratio of 1 part ofsolvent to 1.2 parts of distillate. The mixture of solvent anddistillate was cooled to about 0 FL, whereupon two liquid phases wereformed, one comprising the major portion of the solvent and aromaticand/or naphthenic oil components, and the other comprising undissolvedoil containing a minor portion of solvent. The two phases were separatedfrom one another by decantation and the solvent was removed from each bywashing with a small amount of water, the water thereafter beingseparated from the solvent by distillation. As a result of theextraction, there were produced two gasoline fractions having differentphysical properties and difierent anti-knock values. The dissolvedfraction, in the amount of 37.8% by volume based on the initialdistillate treated, had an A. P. I. gravity of 55.8, an aniline numberof 34.5, and an octane value of '70. The undissolved fraction, in theamount of 62.2% by volume based on the initial distillate treated, hadan A. P. I. gravity of 19.4, an aniline number of 46.2, and an octanevalue of 62.

It will be seen, from the above example, that in accordance with myprocess, there may be produced from a gasoline distillate containingrelatively higher and lower anti-knock value components, a fractionhaving a higher antiknock value and a second fraction having a loweranti-knock value than that of the initial gasoline distillate. In thesame manner, heavier distillates, such as gas oil, may be separated intofractions having respectively higher and lower spontaneous ignitiontemperatures, the latter of which may be suitably employed as animproved compression ignition fuel.

What I claim is:

1. In the solvent refining of mineral oils, the process which comprisesseparating an oil containing paraifinic and naphthenic hydrocarbons intofractions respectively more parafiinic and mor naphthenic than theoriginal oil by extracting said oil with a solvent comprising morpholineand a lower aliphatic alcohol.

2. The method of separating a motor fuel containing components havingrelatively high and lower spontaneous ignition temperatures intofractions respectively richer in higher and lower spontaneous ignitiontemperature components, which comprises commingling said motor fuel witha solvent comprising morpholine and a lower aliphatic alcohol todissolve from said motor fuel the higher spontaneous ignitiontemperature components, separating the solvent containing said dissolvedcomponents from the undissolved lower spontaneous ignition temperaturecomponents and removing solvent from the higher spontaneous ignitiontemperature-components.

3. The method of producing gasoline of improved anti-knock value fromgasoline distillate containing components having relatively higher andlower anti-knock values, which comprises commingling said distillatewith a solvent comprising morpholine and a lower aliphatic alcohol,forming a phase comprising morpholine, lower aliphatic alcohol, and thehigher anti-knock value components, and a second phase comprising thelower anti-knock value components, separating the phases so formed andremoving morpholine and lower aliphatic alcohol from the phase firstmentioned.

4. The method of producing gasoline of improved anti-knock value fromgasoline distillate containing components having relatively higher andlower anti-knock values, which comprises commingling said distillatewith a solvent comprising morpholine and methyl alcohol, forming a phasecomprising morpholine, methyl alcohol, and the higher anti-knock valuecomponents, and a second phase comprising the lower antiknock valuecomponents, separating the phases so formed, and removing morpholine andmethyl alcohol from the phase first mentioned.

5. The method of producing gasoline of improved anti-knock value fromgasoline distillate containing components having relatively higher andlower anti-knock values, which comprises commingling said distillatewith a solvent comprising morpholine and ethyl alcohol, forming a phasecomprising morpholine, ethyl alcohol, and the higher anti-knock valuecomponents, and a second phase comprising the lower anti-knock valuecomponents, separating the phases so formed and removing morpholine andethyl alcohol from the phase first mentioned.

6. In the solvent refining of mineral oils, the process which comprisesseparating an oil containing paraffinic and naphthenic hydrocarbons intofractions respectively more paraffinic and more naphthenic than theoriginal oil by extracting said oil with a solvent comprising a loweraliphatic alcohol and a derivative of morpholine from the groupconsisting of methyl morpholine, ethyl morpholine, and a halogenatedmorpholine.

ARTHUR B. HERSBERGER.

CERTIFICATE OF CORRECTION. Patent No. 2,287,756. Y June 25, 191 2.

- -1mrHUR B. HERSBERGER.

It is hereby certified that error appears in the printed specification Iof the above numbered patent requiring correctionas follows: Page 2,first, column, line 62, for "19.1f read "59.14 and that the said Lettersiatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this day of August, A. D. 19 42.

1 Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

